Instructions

Preheat oven to 375°F. Rub the potato with vegetable oil and prick several times with the tines of a fork. Bake in the preheated oven until tender, about 1 hour. Cut in half and let cool for 10 minutes. Measure out 1 cup of potato flesh; discard the remainder or reserve for another use. Let potato cool.
Insert the metal blade in a Cuisinart® food processor. With the machine running, drop the Parmesan cubes and caraway seeds through the small feed tube, process 15 - 20 seconds, until cheese is finely ground. Add cooled potato, butter, flour, 1/2 teaspoon of the salt, and cayenne. Process until mixture just comes together, but does not completely form a ball, about 10 seconds. Shape into a 1 - inch thick disc. Wrap in plastic wrap, and chill for 15 minutes in the freezer.
Preheat oven to 475°F. Line baking sheets with parchment or a nonstick baking liner. On a lightly floured surface, roll dough out to a 1/4 - inch thick rectangle. In a small bowl, beat the egg with water to make an egg wash. Brush egg wash evenly over pastry surface. Sprinkle evenly with kosher salt. Using a pastry wheel or pizza cutter, cut pastry into 2-1/2 x 1/2 - inch strips. Arrange strips 1 - inch apart on prepared baking sheets. Bake about 12 - 15 minutes until golden brown. Transfer to a rack to cool. May be served slightly warm from the oven or allow to cool completely and store tightly covered in an airtight container.